1. Field of the Invention:
The present invention relates to a jet powered watercraft and more particularly to a watercraft utilizing aligned front and rear skis spaced below a hull and developing lift through the action of water against the ski undersides.
2. Description of Prior Art:
There have been many attempts in the past to provide a waterborne vehicle having a motorcycle-like configuration and characterized by generally the same handling characteristics as a motorcycle. Prior art attempts to produce a satisfactory vehicle have been largely unsuccessful for a number of reasons. The watercraft were either prohibitively expensive to manufacture, difficult to manuever, dangerous in operation due to use of conventional propellers, poor in performance or of short-lived durability.
Prior art motorcycle-like vehicles generally fall into one of two catagories, so-called hydrofoils, which provide lift by action of the water on a completely submerged foil, or hydroskids, which provide lift by action of the water primarily upon the underside of one or more skis riding upon the water surface. The hydrofoil designs are relatively more complex in that they must incorporate some means for controlling the height of the craft above the water.
The present invention is of the hydroskid type, the hydroskids or skis rising to the top of the water upon forward movement of the craft. The craft height is controlled solely by the skidding of the ski or skis upon the water surface.
Use of skis in conjunction with a jet pump presents certain problems. The turbulence generated by the skis as they ride across the water causes air to be entrained in the water moving toward the jet pump inlet. Air induction into the pump greatly detracts from its efficient operation.
A propulsive jet pump should be located such that its discharge nozzle is completely above and as close to the water surface as possible. This minimizes the incoming water path length to the pump and thereby reduces drag and keeps the jet pump above the water to also reduce drag. Such a location means that the jet pump must be disposed between the hull and the top of the rear ski, and consequently there must be a drive connection through the hull to the engine inside the hull. Such a connection poses a severe problem since connections of the engine and the pump to the hull pass their vibrations to the operator, and any flexure of the hull undesirably stresses the connection between the engine and the pump.
Other problems which must be met include the necessity for a self-righting characteristic. The vehicle must come into an upright position even when, for example, it may have just been forced into an upside down position. This means that the engine must be located relatively low in the hull to provide a center of gravity lower than the center of buoyancy. This in turn requires that the engine exhaust and cooling systems must not be susceptible to flooding even though the outside water level may be above most of the engine.
Because of these and other problems, prior art efforts to provide a suitable hydroskid or hydroski watercraft of the character indicated have failed.